Bioassay of heparin and gonadotropins

 

Bioassay of Heparin

Purpose: The bioassay for heparin is used to measure its anticoagulant activity.

Method:

1. In Vivo Assay: Commonly conducted in rabbits or rats. The animals are administered heparin, and then the activated partial thromboplastin time (aPTT) is measured. A comparison is made against a standard heparin preparation.
2. In Vitro Assay: Often involves the use of blood or plasma samples. The anticoagulant effect can be measured by assessing the clotting time after adding heparin to the sample.
3. Comparison to Standard: Results are compared to a standard curve generated from known heparin concentrations to quantify the activity.

Endpoints: The primary endpoint is the increase in aPTT or the degree of inhibition of clot formation.

Bioassay of Gonadotropins

Purpose: The bioassay for gonadotropins (like LH and FSH) assesses their biological activity, primarily in terms of their effect on ovarian or testicular function.

Method:

1. In Vivo Assay: Typically conducted using animal models (e.g., immature rats, mice, or rabbits). The assay measures ovarian or testicular responses, such as follicle maturation or testosterone production.
2. Assessment of Endpoints:
   • Female Mice/Rats: Administering FSH and measuring the number of mature follicles or ovulation rates.
   • Male Mice/Rats: Administering LH and measuring testosterone levels or spermatogenesis.
3. Comparison to Standard: Results are compared against standard preparations of LH or FSH to determine relative potency.

Endpoints: The key endpoints often include hormone-induced changes in reproductive tissues and associated physiological responses.

Conclusion

Both assays are critical for determining the efficacy and potency of these biologically active substances, guiding therapeutic uses and research applications.